A new definitive host for Moniliformis cestodiformis (Acanthocephala: Moniliformidae): first report of a naturally infected European hedgehog (Erinaceus europaeus)

Abstract European hedgehogs, Erinaceus europaeus (Linnaeus, 1758), are small mammals found in western Europe and also in parts of northern Europe. They can be seen in rural, suburban and urban areas, but are usually found in grassland with edge habitats. These animals are omnivorous and serve as definitive or paratenic hosts for several parasites, including acanthocephalans (phylum Acanthocephala). During necropsy of a European hedgehog, a single adult parasite was collected from the intestinal lumen and preserved in 70% ethanol. After morphological evaluation of the specimen, it was identified as Moniliformis cestodiformis (von Linstow, 1904) (Acanthocephala: Moniliformidae). This is the first report of M. cestodiformis in a European hedgehog, as well as in Europe. More epidemiological studies need to be carried out to map the location and prevalence of this parasite in Portugal and the European continent.

Knowledge about the parasites of E. europaeus from mainland Portugal is scarce. Concerning M. cestodiformis, it has only been reported in Erinaceus spp. in West Africa in 1925 (Amin et al., 2016). The present study describes for the first time M. cestodiformis in an E. europaeus specimen and also represents the first report of this parasite in Europe.

Material and Methods
In May 2019, a female European hedgehog in poor physical condition, found in Monsanto forest park, within the municipality of Lisbon, was brought to the Wild Animal Rehabilitation Centre of Lisbon (LxCRAS), together with five offspring. The female stayed with the pups during the first 9 days but, due to her refusal to eat, they were separated. She was treated with natural complementary food (Anima-Strath Ⓡ , 2.5 ml, per os [PO]), a nutritional complement (Duphalyte Ⓡ , 12 ml/kg, PO) and 3 ml of saline solution subcutaneously (SC), at body temperature. On the next day, the female hedgehog was treated with fenbendazole (Panacur Ⓡ , 100 mg/kg, PO). On the 11 th day the animal was warmed up due to hypothermia, but did not survive.
During necropsy, a single adult parasite was collected from the intestinal lumen and preserved in 70% ethanol. The parasite was measured and some eggs were collected. The obtained material was prepared on a slide with Hoyer's medium and observed under an optical microscope. To identify the parasite specimen, an identification key was used (Amin et al., 2016). Information regarding proboscis hooks and their roots, the female reproductive system and gonopore were collected. To confirm the species, proboscis, proboscis receptacle, lemnisci, hooks and its roots, the terminal part of reproductive system and eggs were observed and measured.

Results
The parasite presented a total length of approximately 13 cm ( Figure 1A). Due to its morphological conformation, being round anteriorly and posteriorly and pseudosegmented in-between ( Figure 1A), it was identified as belonging to genus Moniliformis.
Except where millimeters (mm) are indicated, the following measurements are all in micrometers (μm). Proboscis was 475 long and 195 wide ( Figure 1B); it had 16 rows of six to 10 hooks each. Hook blades decreased in size posteriorly. The largest hooks had 23.41 by 9.6 and the smallest 4.78 by 2.06 ( Figures 1C and 1D); hook roots were stout and inserted in the ventral middle part ( Figure 1E); proboscis receptacle was 1.13 mm long and 396 wide ( Figure 1F). Lemnisci was 1.68 mm long and 166 wide posteriorly ( Figure 1F). Regarding the reproductive system, uterus was 640.5 long, and vagina 135.8 long and 32.5 wide ( Figure 1G). Gonopore was nearly terminal ( Figure 1G) and its orifice was 67.7 long in its major axis ( Figure 1H). Eggs were 87.5-95 long by 45-50 wide ( Figure 1I). Likewise, all measurements are in micrometers (μm). Accordingly, the female specimen was identified as Moniliformis cestodiformis (von Linstow, 1904).

Discussion
Parasites are known to have a substantial impact on population dynamics of their hosts (Irvine, 2006). They are a threat to debilitated hedgehogs, frequently leading to morbidity and even death. Some parasites can also represent a zoonotic risk and pose a possible cross infection with pets (Wright, 2014). The hedgehog described in this study was in a poor physical condition and the presence of M. cestodiformis may have impaired its health improvement.
Although several acanthocephalan species have been reported in hedgehogs (Pfäffle, 2011), only a few earlier publications mention M. cestodiformis. This species was originally described in 1904 by von Linstow as Echinorhynchus cestodiformis from two different African species of hedgehogs, Atelerix albventris and Atelerix frontalis (Travassos, 1917). Approximately a century ago, Travassos (1917) transferred it from the genus Echinorhynchus to the genus Moniliformis (Travassos, 1915). Southwell & Macfie raised Moniliformis erinacei as a new species from measurements obtained from a male and a female specimen in Erinaceus spp. from West Africa (Sandground, 1926). According to Amin et al. (2016), these two species, M. cestodiformis and M. erinacei, are the same and the latter must not be considered as valid species.
None of the previous parasitological surveys in European hedgehogs between 1926 and 2016, e.g., Pfäffle et al. (2014), refers to M. cestodiformis. One paper (Amin et al., 2016) includes this species in identification keys and only refers to M. erinacei in Erinaceus spp. from West Africa. The geographical distribution of this parasite is probably not wide enough to be accounted for during hedgehog necropsies or coprological analysis of their feces, as it happens with some other parasites, such as trematode Brachylecithum mackoi in European hedgehogs from Elba island (Casanova & Ribas, 2004).

Conclusion
The present study is a major contribution to the knowledge of the European hedgehog parasitological fauna from Portugal and Europe, providing valuable data concerning M. cestodiformis and bringing to light the first reference in E. europaeus from Portugal and the European continent. More collections and epidemiological studies must be performed to understand its prevalence and localization in Portugal and also in Europe, since work concerning M. cestodiformis is non-existent according to the best of our knowledge.